In order to reduce interconnect delay and capacitance, low dielectric constant (low-k) materials are used as the insulating dielectric for metal wires in integrated circuit (IC) devices. In recent years, low-k (k less than about 3.5) materials have been developed to replace relatively high dielectric constant insulating materials, such as silicon dioxide. In particular, low-k films are being utilized for inter-level and intra-level dielectric layers between metal wires in semiconductor devices. Additionally, some ultra-low k (less than k of about 2.5) material films are formed with pores, i.e., porous low-k dielectric films. Such ultra-low k films can be deposited by a spin-on dielectric (SOD) method similar to the application of photo-resist, or by chemical vapor deposition (CVD). Thus, the use of low-k and ultra-low k materials is readily adaptable to existing semiconductor manufacturing processes.
Low-k and ultra-low k materials are less robust than more traditional silicon dioxide and thus are easily damaged during plasma processing. They also readily absorb moisture in the environment and during wet processing. The inclusion of moisture, plasma damage, and by-products from their forming can adversely affect the electrical performance and reliability of the product.
While existing methods of forming an interconnect have been generally adequate, they have not been entirely satisfactory in every aspect. More efficient methods and chambers that remove unwanted moisture and by-products, and repair damage without increasing the dielectric constant continue to be sought.